The present invention resides in a conveyorized transport apparatus having a rail system for transporting articles carried by a trolley between one location and another and, more particularly relates to a trolley delivery apparatus capable of controllably delivering a trolley from a first location on a subsidiary loop rail to a second diverted location adjacent a workstation.
A conveyorized transport system used for transporting workpieces between a series of subsidiary loops located adjacent individual workstations is disclosed in U.S. Pat. No. 4,615,273 issued on Oct. 7, 1986 and commonly assigned with the assignee of the present invention. Systems of this type usually involve a series of workers situated at workstations on either side or on both sides of the main rail. Individual ones of the trolleys are scanned and then, according to a predetermined program employed by a master computer or controller, diverted toWard a selected one of the workstations located along the main rail. Each operator or worker associated with a particular workstation is charged with a given function to perform on the workpiece carried by the diverted trolley when it arrives at the associated workstation. These workers may repeat the same work function several hundred times over the course of a workday in performance of that work function. The trolleys traveling on the main rail are diverted from the main rail system onto subsidiary loops and are usually stopped on these subsidiary loops by gates where Work material carried by respective ones of the trolleys await performance of a work function by an operator situated at the workstation.
The problem associated with these gates is that often they are situated along the subsidiary loop rail such that a stopped trolley and the workpiece carried by it are suspended on a portion of the subsidiary loop at a considerable distance above and away from the operator. Consequently, the operator usually must reach across this distance from a position adjacent his or her workstation to attempt to grasp the workpiece carried by the trolley which has stopped at the gate. Such extended grasping movements tend to exhaust the operator during the course of the workday thus robbing him or her of valuable time and energy which otherwise could be applied toWard the work function at hand. Thus, a clear need for an economically efficient workstation is apparent in order to situate workpieces adjacent a perspective worker so as to minimize the total number of movements required of the worker or operator in performance of a particular work function and thereby maximize efficiency of productivity.
Other devices have been developed which address this problem. One such type of device is disclosed in the U.S. Pat. No. 4,840,123 issued on June 20, 1989. In this patent, the rail of a subsidiary loop is positioned adjacent a workstation with a portion of this rail being capable of pivotal movement through two orthogonally oriented planes so as to position a trolley, carried at the free swinging end of the rail segment, adjacent a workstation. While such a device has been successful in increasing the ergonomic capability of the worker at a given workstation, it is however sometimes desirable to deliver a trolley carrying a workpiece to a workstation without having to sWing a rail segment through any angular movement. Also, it has been found that significant mechanical means are needed to effect pivotal movement of the arm in this patent, requiring both a complex control system and a variety of multifaceted moving parts.
Also, in the aforesaid co-pending U.S. Application No. 400,290, entitled VARIABLE HEIGHT WORKSTATION AND SYSTEM, a trolley delivery apparatus is disclosed which automatically delivers a trolley from a subsidiary loop rail to a workstation. While such trolley delivery apparatus have been found to greatly enhance the ergonomic capabilities of the worker at his or her workstation, such apparatus have sometimes however been problematic in that they do not allow the operator the option of either lowering the involved trolley to the workstation or, instead to allow the trolley to pass through the workstation without being lowered.
Accordingly, it is an object of the present invention to provide variable height workstation capable of controllably diverting a trolley from a subsidiary loop to a workstation or, instead of such diverting action, allowing the involved trolley to travel along the subsidiary loop without being so diverted.
It is yet another object of the present invention to provide a workstation capable of efficiently managing the travel of trolleys through subsidiary loop and back onto the main rail from which main rail the trolleys were originally diverted.
Still a further object of the present invention is to provide a conveyorized transport apparatus capable of routing trolleys to an operator performing a work function at a workstation on a workpiece carried by a diverted trolley traveling on the subsidiary loop rail such that the operator accomplishes this task with maximum ergonomic ease.